Netconsole in u-Boot-2013.01 seems to be broken. The 2nd character in a command somehow got dropped, and u-boot sees it as a wrong command.

Here is the log:

U-Boot 2013.01 (May 03 2013 - 23:04:51) Seagate GoFlex Net gcc (Debian 4.6.3-1) 4.6.3 GNU ld (GNU Binutils for Debian) 2.22 Hit any key to stop autoboot: 6 0 GoFlexNet> printenv pintenv Unknown command 'pintenv' - try 'help' GoFlexNet> prrintenv printenv ....

So I booted the box with:

GoFlexNet> boot bot Unknown command 'bot' - try 'help' GoFlexNet> booot boot (Re)start USB... ....

After this, the system did not complete booting Linux.